A class of very large flexible radar arrays, used to implement electronically scanned array (ESA) radars, is needed for a number of future applications. These ESA arrays are flexible and mounted in airborne platforms with propulsion systems and other sources of input motion. Due to the flexible nature of the arrays, their shape is dynamic and often needs to be measured. Flexible arrays have often been measured by optical systems that directly determine array shape and orientation. Most arrays, whether considered flexible or not, have an inertial navigation service that uses either inertial instruments (usually an integrated navigation system or INS) that is co-located with the array, as with most fighter radars. In cases where co-location of an INS is not possible for packaging reasons, an additional inertial instrument such as a small inertial measurement unit (IMU) may be co-located with the array and used for local motion measurement, as is the case for some large surveillance radars.
For very large flexible arrays, use of a co-located inertial instrument is often impractical because of the size and scale of the array. In addition, a single inertial instrument often cannot be physically attached to the array or its suspension system rigidly enough, nor is the array itself generally rigid enough, to ensure adequate knowledge of the dynamic motion of the array. However, optical systems have not yet been devised that allow for measurement of such a large array at the temporal and spatial resolution that is generally needed to support beam forming for an ESA radar. As such, there is a need for a system and method for determining the position, orientation, and shape of an airborne radar array.